Sheet steel draw die

ABSTRACT

A draw die assembly for extruding sheet steel material and the like comprising a pair of opposed dovetail shaped dies supported within complementally formed slots located in a pair of die holder members. A plurality of wear plates are interposed between the inner periphery of the slot and the engaging surfaces of the dies whereby to facilitate removal of the dies for sharpening or regrinding. In one form of the invention, three pairs of dies are provided with each pair being adapted to successively reduce the thickness of the material. In a second form of the invention, the thickness of the material is reduced by integral multi-drawing blades disposed in each of a single pair of opposed die elements.

United States Patent [1 1 Maiale 1 Aug. 6, 1974 SHEET STEEL DRAW DllEPrimary ExaminerMilton S. Mehr [76] Inventor: Louis J. Maiale, 3831 w.Paint St., Attorney Agent FimHam@SS Dickey & Pierce Dearborn, Mich.48204 [22] Filed: Apr. 23, 1973 ABSTRACT [2]] Appl. No.: 353,596 A drawdie assembly for extruding sheet steel material and the like comprisinga pair of opposed dovetail shaped dies supported within complementallyformed [52] Cl 2 5 3 5? slots located in a pair of die holder members. Aplural- 51] Int Cl T 37/02 ity of wear plates are interposed between theinner pe- [58] d 366 riphery of the slot and the engaging surfaces ofthe g g l 90 f dies whereby to facilitate removal of the dies for 81 1sharpening or regrinding. In one form of the invention, three pairs ofdies are provided with each pair being [56] R f Ct d adapted tosuccessively reduce the thickness of the e erences l e material. In asecond form of the invention, the thick- UNITED STATES PATENTS ness ofthe material is reduced by integral multi 1,103,927 7/1914 Audibert81/180 B drawing blades disposed in each of a single pair of op-2,l78,674 ll/l939 Simons 72/205 posed die elements,

R22,737 4/1946 Bailey 72/90 8 Claims, 5 Drawing Figures 4 m Z a" i 17 5(I I V L t- 4 ii 55 if 57 J it '1' j i 7Z4] 4 )1 [Z4 j g L L TL A 24 /212 f4 a ,5 24 4 e SHEET STEEL DRAW DIE BACKGROUND AND SUMMARY OF THEINVENTION The present disclosure relates generally to the processing offerrous metals, and more particularly to a new and improved method andapparatus for drawing sheet steel.

Generally speaking, sheet steel is mass produced for commercial andindustrial applications by a process which typically includes both hotworking and cold working the material. With respect to the former,rolling usually is the first step in converting ingots into finishedparts. The rolling process consists of passing hot metal between rollerswhich revolve in opposite directions, and which the spacing therebetweenis less than the thickness of the material entering, whereby thematerial is both squeezed and elongated and usually altered in crosssection. This results in plastic deformation and accompanying grainrefinement of the material when the rolling is accomplished at suitabletem peratures. Thereafter to further improve the surface finish and toobtain greater dimensional accuracy, the material is generally subjectedto a cold working process, such as by way of example, cold rolling.

One disadvantage, however, of cold working the material resides in theneed for special preparation of the hot worked material. In this regard,the scale of the material should be removed to avoid abrasion andpitting of the cold working apparatus. Scale removal is accomplished bya pickling process in which the metal is submerged in acid andthereafter washed. Frequently, the material is also subjected to a lightcold rolling operation and in some instances the material can beannealed.

In the present invention, the material is extruded or drawn after theegress from a hot rolling mill at a high temperature level. Thus, theneed for pickling the material is in most instances obviated, and theadvantages for subsequently cold working are greatly diminished. It,therefore, is a general object of the subject invention to provide aprocess for extruding or drawing a sheet steel material which willprovide an alternative to pickling and cold working and thereby reducethe manufacturing cost.

The present invention is comprised of one or more opposed andselectively spaced pairs of dies for drawing or extruding the materialas it is drivingly forced therebetween. Due to the abrasive and pittingaction of the material as it is extruded by the dies, it is desirablethat the dies be easily removed to facilitate sharpening or regrinding.In the present invention, the dies have a triangular shaped crosssection with an apex defining the drawing blade surface. The sideopposite the apex is adapted to be located in a dovetailed slot. Aplurality of wear plates are interposed between adjacent seatingsurfaces of each of the dies and slots, and the dies and slots are eachtapered in a lateral direction relative to the longitudinal movement ofthe material whereby the die is easily freed in response to slightlateral movement, Conversely, when the die is being installed, it iseasily located due to the initially relatively large clearancetherebetween. It is, therefore, another object of the-subject inventionto provide a combination die and holder therefor wherein the dies areeasily installed or removed.

In one form of the invention, a plurality of longitudinally spaced andopposed sets of dies are supported in a holder in such a manner that thethickness of the material is successively reduced. All. of the dies andcooperating slots are dimensionally uniform but wear plates of varyingdimensions are provided to successively decrease the openings betweenadjacent pairs of dies. The result is universality of application withrespect to the dies and uniform machining for the slots. It, therefore,is another object of the subject invention to provide an apparatus fordrawing sheet metal utilizing a uniform die construction which islocatable in a uniformly machined holder member.

In a second form of the invention a single pair of opposed multi-bladedor toothed dies are identically supported as in the first form, butdisposed on an inclined surface of a wear plate. By providing a set ofwear plates having an upper surface with varying degrees of inclinationand by having one of the holders opposingly movable relative to theother, it is possible to adjust the bite or opening between the dieblades. It, therefore, is a further object of the present invention toprovide a system of wear plates which are adapted to selectively adjustthe opening between opposed dies.

Other objects, features and advantages of the present invention willbecome apparent from the following detailed description taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of an exemplarydraw die assembly in accordance with a preferred first form of thepresent invention, and a fragmentary representation of a hot rollingmill;

FIG. 2 is a cross-sectional view of the assembly illustrated in FIG. 1taken long the lines 22 thereof;

FIG. 3 is a fragmentary side view of an exemplary draw die assembly inaccordance with a preferred second form of the present invention;

FIG. 4 is a cross-sectional view of the assembly illustrated in FIG. 3taken along the lines 4-4 thereof; and

FIG. 5 is an enlarged view of the closed within the circle 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS For convenience ofdescription, the terms upper, lower," right, left" and words of similarimport will have reference to the various members and components of thedraw die assembly of the present invention as arranged and illustratedin FIGS. 1-5 of the drawings and described hereinafter in detail.Likewise, the terms inner," outer and derivatives thereof, will havereference to the geometric center of such members and the variousportions or sections thereof.

With reference now to FIG. 1 of the drawings, an exemplary firstpreferred embodiment of the subject draw die assembly is indicatedgenerally at 10 and disposed down stream or to the right of a hotrolling mill 12. Generally speaking, the mill I2 is comprised of aseries of rolling stands wherein ingots are first rolled into blooms andsubsequently rolled in tages to form billets or slabs. The mill 12 canbe assumed to be of any conventional construction or arrangement andforms no part of the subject invention. By way of example, however, andfor purpose of explanation, the final stage of portion of FIG. 3 enthemill 12 isshown as being comprised of a pair of rollers 14 and 16 whichare adapted to revolve in opposite directions. The spacing between therollers 14 and 16 is less than the thickness of the material enteringwhereby the material is squeezed and elongated and correspondinglychanged in ross sectional shape. At the same time, due to the appliedforce of the rollers 14 and 16, the material also undergoes a plasticdeformation accompanied by grain refinement which results in a moreuniform and standardized product. For purposes of illustration, anexemplary section of work stock 18 is shown at 20 as being deformablysqueezed in accordance with the spacing between the rollers 14 and 16.Moreover and also for purposes of illustration, the assembly can bedisposed on the right or down stream side of the hot rolling mill 12whereby the workpiece can be directly driven therein, or alternatively aseparate pulling or driving means can be provided for conveying the workstock 18 therethrough. As will hereinafter be described, the assembly 10is adapted to draw or extrude the work stock 18 whereby to obviate anyfurther processing as is now conventional in the art.

In his regard, the assembly 10 is comprised of a plurality oftriangularly shaped, laterally extending die elements 26, 28, 30, 32, 34and 35 which are arranged in opposed sets and removably supported byupper and lower die holder members indicated generally at 22 and 24respectively. The members 22 and 24 are in turn connected to a suitablesupport structure (not shown) which includes means for adjustablylocating the adjacent confronting surfaces thereof and accordingly, theopening or distance between the opposed die elements as shallhereinafter become apparent. In this regard both of the members 22 and24 can be movably supported or one can be immovably fixed with the otherbeing movably. In the form illustrated in FIG. 1 of the invention, itwill be assumed that the lower member 24 is fixed and the upper member22 is suitably supported by the support structure for movement in avertical direction relative to the member 24. The member 22 is providedwith a plurality of longitudinally spaced, dovetail shaped grooves 38,42 and 46 conforming in number to the dies, with each groove 38, 42 and46 being adapted to support the die elements 28, 32 and 35 respectively.Correspondingly, the lower die holder member 24 is adapted to supportthe die elements 32, 34 and 35 in comparably formed, dovetail shapedgrooves 36, 40 and 44 respectively. In accordance with a preferred formof the assembly 10, each of the die elements 26, 28, 30, 32, 34 and 35are dimensionally identical and interchangeable whereby to providestandardization in the fabrication thereof. Moreover, the grooves 36,38, 40,42, 44 and 46 are each dimensionally identical and of uniformshape and configuration. In the subject invention each of the elements26, 28, 30, 32, 34 and 35 are removably supported in the grooves 36, 38,40, 42, 44 and 46 respectively by a system of wear plates or pads whichfacilitates standardization of components and which further functions toprecisely locate the opposed sets of die elements 26 and 28, 30 and 32,and 34 and 35 in preselected spaced relationship whereby the thicknessof the work stock 18 can be successively decreased as it islongitudinally displaced across the assembly 10.

Because of the general uniformity and similarity of the die elements andidentical cooperating grooves, the

system of wear plates will be described solelyfor the die element 26 andcooperating dovetail shaped groove 36, it being appreciated that theremaining elements and grooves are substantially identical subject to adimensional variance which will hereinafter be described. The element 26is comprised of a pair of inclined side walls 48 and 50, a lower basesurface 54, and an upper working surface 52 which is adapted toengageably extrude or draw the workpiece l8. Correspondingly, the groove36 is formed by a lower base surface 64 and a pair of inclined side wallsurfaces 62 and 66. A lower wear plate 54 is interposed between the basesurfaces 54 and 64 of the die element 26 and groove 36 respectively. Ina similar manner a pair of side wear plates 56 and 58 are respectivelyinterposed between the confronting side surfaces 48 and 62, and 50 and66 of the die 26 and the groove 36. It will be noted that each of thewear plates 58, 60 and 56 are precisely machined to previouslydetermined dimensions whereby to nestingly locate the element 26relative to the groove 36 and locate the working surface 52 in fixedspaced relationship relative to the confronting upper surface of theholder 24.

To facilitate installation and removal of the die 26 in the groove 36for purposes of sharpening or regrinding the working surface 52 of theelement 26, the die 26 and groove 36 are each formed in a laterallyextending, tapered relationship which is best seen in FIG. 2. Withreference thereto, it will be seen that the oppositely spaced edges 52aand 52b defining the work surface 52 are convergent in the directionindicated by arrow 51. In a like manner, each of the side walls 48 and50 and the base surface 54 have similarly convergent edges whereby thetransverse cross section of the die element 26 also decreases in thedirection of the arrow 51. In accordance therewith the slot 36 is formedof a complemtnary construction to cooperatively and slidably receive thedie 26 in a manner whereby the die 26 can be initially inserted with theengaging surfaces thereof and the wear plates in spaced relationship,i.e. at least up to a certain point at which a tight friction fit willoccur to lockingly engage the element 26 therein. It will be noted thatthe purpose of this feature significantly minimizes the effort toextract the die from the die holder and easily facilitates itsreinsertion.

In the subject invention the wear plates are provided in sets foraccommodation of opposed die elements such as by way of example, theelements 26 and 28. In this regard, it will be seen that the die element28 is supported by an upper wear plate 59 and a pair of side wear plates57 and 55, the plates being identical to the wear plates 54, 56 and 58respectively. In a like manner, the next set of die elements 30 and 32are identically supported but since the opening between the workingsurfaces thereof is adapted to further extrude the workpiece 18, thethickness of each of a pair of identical wear plates 61 and 62 isincreased relative to the thickness of the wear plates 59 and 60. In alike manner, a pair of wear plates 63 and 64 of still greater increasedthickness relative to the wear plates 61 and 62 are utilized to supportthe next adjacent set of die elements 34 and 35. Accordingly, each ofthe side wear plates supporting the sets of die elements 30 and 32, and34 and 35 are correspondingly formed of decreased thickness in thedirection of travel of the work stock 18 to accommodate the increasedextention of the upper and lower wear plates and the resulting opposeddecreased opening therebetween. Although three sets of elements areillustrated in FIG. ll, it will be understood that additional sets ofdie elements may be provided in the assembly whereby the degree ofextrusion of each set of elements can be increased or de creased foraccommodation of a particular type of work stock 18.

For some applications, it may be desirable to utilize a single dieelement having multiple working or cutting surfaces in lieu of theplurality of die elements provided in the embodiment illustrated inFIG. 1. In this regard and with reference to FIGS. 3, 4 and 5, a secondpre ferred form of the subject draw die assembly is indicated generallyat 70. In a manner analogous to the construction previously described inconjunction with the first embodiment, the assembly 70 is comprised ofupper and lower die holders 74 and 72 which are again suitably connectedto a support structure which includes the provision of adjustablyspacing one of the holders 74 or 72 vertically relative to the other.Each of the holder 74 and 72 includes laterally extending, dovetailshaped grooves or recesses 82 and 80 respectively which are adapted tosupport a pair of multiedged die elements 78 and 76. The die element 78is supported in the groove 82 by an upper wear plate or pad 92 and apair of side wear plates 90 and 94. In a like manner, the die element 76is supported in the groove 80 by a lower wear plate 86 and a pair ofside plates 84 and 88. As best seen in FIG. 4, the element 76 and groove80 are each convergently tapered in a lateral direction corresponding tothe arrow 51 in FIG. 2 whereby to provide the same advantages withrespect to installation or removal to the die element 76. With respectto the opposed die element 78 and groove 82, the configuration andarrangement is identical and a mirror image of element 76 and groove 80respectively.

With reference to FIG. 5, the element 76 includes three working orcutting edges 98, 100 and 102 which are formed on the upper surfacethereof. To successively reduce the thickness of a section of work stockas it is driven across the die 76, the edges are inclined by virtue ofbeing supported on an inclined uppe surface of the lower wear plate 86.By providing wear plates in matched sets differing from one another bythe angle of inclination of the upper surface, it is possible to againprovide selective control of the degrees or draw of extrusionattributable to each of the edges 98, 100 and 1102. Thus, the samedegree of versatility can be incorporated in the second preferred formof the subject invention as was incorporated in the first form.

From the foregoing it will be seen that in the operation of the assembly10 or 70, that a section of work stock is drawn or extruded in responseto longitudinal displacement across the working surfaces thereof. As aresult of the additional processing of the work stock, the normallyadditional conventional steps of pickling and subsequent cold rollingcan be eliminated to provide a substantial savings in manufacturingcosts. It will further be noted that a distinct advantage of the subjectinvention resides in the provision for an easy and expedient removal ofthe individual die elements to facilitate regrinding and sharpening andthe subsequent reinstallation of the die elements in the assembly.Moreover, the provision of standard die elements loeatable in uniformlyconstructed recesses which is accomplished through the provision of thewear plates is adapted to provide still another advantage.

While it will be apparent that the preferred embodiments of the sheetsteel draw die illustrated herein are well calculated to fulfill theobjects above stated, it will be appreciated that the present inventionis susceptible to modification, variation and change without departingfrom the scope of the invention.

What is claimed is:

1. A draw die assembly for extruding work stock comprising: an opposedpair of spaced die elements adapted for extruding the work stock; spacedapart holder means for said pair of die elements which are spaced apredetermined distance apart thereby; pad means interposed between saidholder means and said die elements to preclude wear on said holdermeans; and means for feeding said work stock between said die elementsfor reducing the thickness thereof.

2. The assembly as recited in claim 1 wherein each of said die elementshave a triangularly shaped cross section and wherein said holder meanshas a dovetailed recess for receiving one of said die elements.

3. The assembly as recited in claim 2 wherein said recess extendslaterally relative to the movement of said work stock and wherein eachof said recess and die elements are tapered in a lateral direction tofacilitate removal and installation of said die elements.

4. The assembly as recited in claim 2 wherein said holder meanscomprises first and second holder members, and which includes means formoving one of said members relative to the other member to selectivelyadjust the spacing between said die elements.

5. The assembly as recited in claim 2 wherein said pad means includes aplurality of wear plates interposed between saId die elements and saidholder means.

6. The assembly as recited in claim 5 wherein each of said die elementsinclude more than one working surface and wherein said more than oneworking surfaces are inclined relative to the direction of travel of thework stock.

7. The assembly as recited in claim 6 wherein one of said wear platesincludes an inclined surface for supporting one of said die elements.

8. The assembly as recited in claim 1 which includes a plurality ofadditional pairs of die elements, and wherein said additional pairs ofdie elements are also supported by said holder means for reducing thethickness of the stock seriatim as it passes from one pair of dieelements to another.

1. A draw die assembly for extruding work stock comprising: an opposedpair of spaced die elements adapted for extruding the work stock; spacedapart holder means for said pair of die elements which are spaced apredetermined distance apart thereby; pad means interposed between saidholder means and said die elements to preclude wear on said holdermeans; and means for feeding said work stock between said die elementsfor reducing the thickness thereof.
 2. The assembly as recited in claim1 wherein each of said die elements have a triangularly shaped crosssection and wherein said holder means has a dovetailed recess forreceiving one of said die elements.
 3. The assembly as recited in claim2 wherein said recess extends laterally relative to the movement of saidwork stock and wherein each of said recess and die elements are taperedin a lateral direction to facilitate removal and installation of saiddie elements.
 4. The assembly as recited in claim 2 wherein said holdermeans comprises first and second holder members, and which includesmeans for moving one of said members relative to the other member toselectively adjust the spacing between said die elements.
 5. Theassembly as recited in claim 2 wherein said pad means includes aplurality of wear plates interposed between saId die elements and saidholder means.
 6. The assembly as recited in claim 5 wherein each of saiddie elements include more than one working surface and wherein said morethan one working surfaces are inclined relative to the direction oftravel of the work stock.
 7. The assembly as recited in claim 6 whereinone of said wear plates includes an inclined surface for supporting oneof said die elements.
 8. The assembly as recited in claim 1 whichincludes a plurality of additional pairs of die elements, and whereinsaid additional pairs of die elements are also supported by said holdermeans for reducing the thickness of the stock seriatim as it passes fromone pair of die elements to another.